Systems and Methods for Utilizing Gravity to Determine Subject-Specific Information

ABSTRACT

A system for measuring data specific to a subject using gravity comprises a substrate on which a subject lies, the substrate having multiple legs extending from the substrate to a floor to support the substrate, and load sensor assemblies. Each load sensor assembly is associated with a respective leg and comprises a cap configured to receive a load from the substrate, a base configured to provide contact with the floor, the base and cap configured to fit together to maintain alignment of the cap to the base while allowing vertical movement of the cap, a load cell between the base and the cap, one of the base and cap configured to translate the load to the load cell and a printed circuit board that processes and outputs data from the load cell, wherein a combination of all load sensor assemblies receive an entire load to which the substrate is subjected.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.16/551,087, filed Aug. 26, 2019, which claims priority to and thebenefit of U.S. Provisional Application Patent Ser. No. 62/804,623,filed Feb. 12, 2019, the entire disclosure of which is herebyincorporated by reference.

TECHNICAL FIELD

This disclosure relates to systems and methods for sensing biometricsand other subject-specific information of one or more subjects usingmultiple sensors that are not in contact with the subjects.

BACKGROUND

Sensors have been used to detect heart rate, respiration and presence ofa single subject using ballistocardiography and the sensing of bodymovements using noncontact methods, but are often not accurate at leastdue to their inability to adequately distinguish external sources ofvibration and distinguish between multiple subjects. In addition, thenature and limitations of various sensing mechanisms make it difficultor impossible to accurately determine a subject's biometrics, presence,weight, location and position on a bed due to factors such as airpressure variations or the inability to detect static signals.

SUMMARY

Disclosed herein are implementations of systems for measuring dataspecific to a subject using gravity. One such system comprises asubstrate on which a subject lies, the substrate having multiple legsextending from the substrate to a floor to support the substrate, andload sensor assemblies. Each load sensor assembly is associated with arespective leg and comprises a cap configured to receive a load from thesubstrate, a base configured to provide contact with the floor, the baseand cap configured to fit together to maintain alignment of the cap tothe base while allowing vertical movement of the cap, a load cellbetween the base and the cap, one of the base and cap configured totranslate the load to the load cell and a printed circuit board thatprocesses and outputs data from the load cell, wherein a combination ofall load sensor assemblies receive an entire load to which the substrateis subjected.

Another embodiment of a system for measuring data specific to a subjectusing gravity comprises a substrate on which a subject rests, thesubstrate having multiple legs extending from the substrate to a floorto support the substrate, at least two load sensor assemblies, each loadsensor assembly associated with a respective leg configured to measure astatic load and changes in load on the substrate through the leg, acontroller and communication means from each of the at least two loadsensor assemblies to the controller, wherein the controller processesoutput from each of the at least two load sensor assemblies.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure is best understood from the following detaileddescription when read in conjunction with the accompanying drawings. Itis emphasized that, according to common practice, the various featuresof the drawings are not to-scale. On the contrary, the dimensions of thevarious features are arbitrarily expanded or reduced for clarity.

FIG. 1 is schematic of a system for measuring data specific to a subjectusing gravity.

FIGS. 2A and 2B are schematics of a load sensor assembly as disclosedherein.

FIGS. 3A and 3B are embodiments of load sensor assemblies as disclosedherein.

FIGS. 4 and 5 are embodiments of systems for measuring data specific toa subject using gravity.

FIGS. 6A and 6B are schematics of a system for measuring data specificto a subject using gravity using a floor mat.

FIG. 7 is a schematic of a system for measuring data specific to asubject using gravity incorporated into a floor.

FIG. 8 is an exploded view of another embodiment of a load sensorassembly as disclosed herein.

FIG. 9 is a schematic of a leg of a substrate incorporating anaccelerometer sensor assembly.

FIGS. 10A and 10B are schematics of a system incorporating an opticalvibration sensor as disclosed herein.

FIGS. 11A and 11B are schematics of a knife edge sensor assembly asdisclosed herein.

FIGS. 12A and 12B are schematics of an optical encoder sensor assemblyas disclosed herein.

FIGS. 12C-12G are embodiments of templates used with the optical encodersensor assembly.

FIGS. 13A-13C are schematics of a polarized sensor assembly as disclosedherein.

FIG. 14 is a schematic of a fiber optics power source for the systemsdisclosed herein.

FIG. 15A is a plan view of a system for measuring data specific to onesubject using gravity.

FIG. 15B is a plan view of a system for measuring data specific to twosubjects using gravity.

FIG. 16 is a diagram of signal adding to increase signal strength.

FIG. 17A is a schematic of a system for measuring data specific to asubject using gravity and canceling out external noise.

FIG. 17B is a diagram of signal cancelation to remove external noise.

FIG. 18A represents different loads on the load sensor assemblies basedon a sleeping position.

FIG. 18B represents the loads on the load sensor assemblies based onanother sleeping position.

FIG. 19 is a schematic illustrating a substrate having legs that lowerthe substrate to accommodate a subject exiting the substrate.

FIG. 20 represents the loads on the load sensor assemblies based on yetanother sleeping position.

DETAILED DESCRIPTION

Disclosed herein are implementations of systems and methods employinggravity and motion to determine biometric parameters and otherperson-specific information for single or multiple subjects at rest andin motion on one or multiple substrates. The systems and methods usemultiple sensors to sense a single subject's or multiple subjects' bodymotions against the force of gravity on a substrate, including beds,furniture or other objects, and transforms those motions into macro andmicro signals. Those signals are further processed and uniquely combinedto generate the person-specific data, including information that can beused to further enhance the ability of the sensors to obtain accuratereadings. The sensors are connected either with a wire, wirelessly oroptically to a host computer or processor which may be on the internetand running artificial intelligence software. The signals from thesensors can be analyzed locally with a locally present processor or thedata can be networked by wire or other means to another computer andremote storage that can process and analyze the real-time and/orhistorical data.

The sensors are designed to be placed under, or be built into asubstrate, such as a bed, couch, chair, exam table, floor, etc. Thesensors can be configured for any type of surface depending on theapplication. Additional sensors can be added to augment the system,including light sensors, temperature sensors, vibration sensors, motionsensors, infrared sensors and sound sensors as non-limiting examples.Each of these sensors can be used to improve accuracy of the overalldata as well as provide actions that can be taken based on the datacollected. Example actions might be: turning on a light when a subjectexits a bed, adjusting the room temperature based on a biometric status,alerting emergency responders based on a biometric status, sending analert to another alert based system such as: Alexa, Google Home or Skifor further action.

The data collected by the sensors can be collected for a particularsubject for a period of time, or indefinitely, and can be collected inany location, such as at home, at work, in a hospital, nursing home orother medical facility. A limited period of time may be a doctor's visitto assess weight and biometric data or can be for a hospital stay, todetermine when a patient needs to be rolled to avoid bed sores, tomonitor if the patient might exit the bed without assistance, and tomonitor cardiac signals for atrial fibrillation patterns. Messages canbe sent to family and caregivers and/or reports can be generated fordoctors.

The data collected by the sensors can be collected and analyzed for muchlonger periods of time, such as years or decades, when the sensors areincorporated into a subject's personal or animal's residential bed. Thesensors and associated systems and methods can be transferred from onesubstrate to another to continue to collect data from a particularsubject, such as when a new bed frame is purchased for a residence orretrofitted into an existing bed or furniture.

The highly sensitive, custom designed sensors detect wave patterns ofvibration, pressure, force, weight, presence and motion. These signalsare then processed using proprietary algorithms which can separate outand track individual source measurements from multiple people, animalsor other mobile or immobile objects while on the same substrate.

These measurements are returned in real-time as well as tracked overtime. Nothing is attached to the subject. The sensors can beelectrically or optically wired to a power source or operate onbatteries or use wireless power transfer mechanisms. The sensors and thelocal processor can power down to zero or a low power state to savebattery life when the substrate is not supporting a subject. Inaddition, the system may power up or turn on after subject presence isdetected automatically.

The system is configured based on the number of sensors. Because thesystem relies on the force of gravity to determine weight, sensors arerequired at each point where an object bears weight on the ground. Forother biometric signals fewer sensors may be sufficient. For example, abed with four wheels or legs may require a minimum of four sensors, alarger bed with five or six legs may require five for six sensors, achair with four legs would may require sensors on each leg, etc. Thenumber of sensors is determined by the needed application. The uniqueadvantage of multiple sensors provides the ability to map and correlatea subject's weight, position and bio signals. This is a clear advantagein separating out a patient's individual signals from any other signalsas well as combining signals uniquely to augment the signals for aspecific biosignal.

The system can be designed to configure itself automatically based onthe number of sensors determined on a periodic or event-based procedure.A standard configuration would be four sensors per single bed with fourlegs to eight leg sensors for a multiple person bed. The system wouldautomatically reconfigure for more or less sensors. Multiple sensorsprovide the ability to map and correlate a subject's weight, positionand bio signals. This is necessary to separate multiple subjects'individual signals.

Some examples of the types of information that the disclosed systems andmethods provide are dynamic center of mass and center of signallocations, accurate bed exit prediction (timing and location of bedexit), the ability to differentiate between two or more bodies on a bed,supine/side analysis, movement vectors for multiple subjects and otherobjects or animals on the bed, presence, motion, position, direction andrate of movement, respiration rate, respiration condition, heart rate,heart condition, beat to beat variation, instantaneous weight and weighttrends, and medical conditions such as heart arrhythmia, sleep apnea,snoring, restless leg, etc. By leveraging multiple sensors that detectthe z-axis and other axes of the force vector of gravity, and bydiscriminating and tracking the center of mass or center of signal ofmultiple people as they enter and move on a substrate, not only can thedisclosed systems and methods determine presence, motion and cardiac andrespiratory signals for multiple people, but they can enhance thesignals of a single person or multiple people on the substrate byapplying the knowledge of location to the signal received. Secondaryprocessing can also be used to identify multiple people on the samesubstrate, to provide individual sets of metrics for them, and toenhance the accuracy and strength of signals for a single person ormultiple people. For example, the system can discriminate betweensignals from an animal jumping on a bed, another person sitting on thebed, or another person lying in bed, situations that would otherwiserender the signal data mixed. Accuracy is increased by processingsignals differently by evaluating how to combine or subtract signalcomponents from each sensor for a particular subject.

Additional sensor types can be used to augment the signal, such as lightsensors, temperature sensors, accelerometers, vibration sensors, motionsensors and sound sensors.

FIG. 1 illustrates a system 1 for measuring data specific to a subjectusing gravity. The system 1 can comprise a substrate 10 on which asubject 12 can lie, the substrate 10 having multiple legs 14 extendingfrom the substrate 10 to a floor 16 to support the substrate 10.Multiple load sensor assemblies 20 can be used, each load sensorassembly 20 associated with a respective leg 14 of the substrate 10. Anypoint in which a load is transferred from the substrate 10 to the floor16 should have an intervening load sensor assembly 20.

As illustrated in FIG. 1 , a local controller 18 can be wired orwirelessly connected to the load sensor assemblies 20 and collects andprocesses the signals from the load sensor assemblies 20. The controller18 can be attached to the frame of the substrate so that it is hiddenfrom view, can be under the substrate or can be positioned anywhere awireless transmission can be received from the load sensor assemblies 20if transmission is wireless. The controller 18 can be programmed tocontrol other devices based on the processed data as discussed below,the control of other devices also being wired or wireless.Alternatively, or in addition to, an off-site controller 21 or acloud-based network 23 can collect the signals directly from the loadsensor assemblies 20 for processing or can collect raw or processed datafrom the local controller 18. For example, the local controller 18 mayprocess the data in real time and control other local devices asdisclosed herein, while the data is also sent to the off-site controller21 that collects and stores the data over time. The controller 18 or 21may transmit the processed data off-site for use by downstream thirdparties such as medical professionals, fitness trainers, family members,etc. The controller 18 or 21 can be tied to infrastructure that assistsin collecting, analyzing, publishing, distributing, storing, machinelearning, etc. Design of real-time data stream processing has beendeveloped in an event-based form using an actor model of programming.This enables a producer/consumer model for algorithm components thatprovides a number of advantages over more traditional architectures. Forexample, it enables reuse and rapid prototyping of processing andalgorithm modules. As another example, it enables computation to belocation-independent (i.e., on a single device, combined with one ormore additional devices or servers, on a server only, etc.)

The long-term collected data can be used in both a medical and homesetting to learn and predict patterns of sleep, illness, etc. for asubject. As algorithms are continually developed, the long-term data canbe reevaluated to learn more about the subject. Sleep patterns, weightgains and losses, changes in heart beat and respiration can together orindividually indicate many different ailments. Alternatively, patternsof subjects who develop a particular ailment can be studied to see ifthere is a potential link between any of the specific patterns and theailment.

The data can also be sent live from the local controller 18 or theoff-site controller 21 to a connected device 19, which can be wirelesslyconnected for wired. The connected device 19 can be, as examples, amobile phone or home computer. Devices can subscribe to the signal,thereby becoming a connected device 19.

As illustrated in FIGS. 2A and 2B, each load sensor assembly 20comprises a cap 22 configured to receive a load from the substrate 10and a base 24 configured to provide contact with “ground”, or the floor16, the base 24 and cap 22 configured to fit together to maintainalignment of the cap 22 to the base 24 while allowing vertical movementof the cap 22. The base's contact with the floor 16 can be direct orindirect, such as through the leg 14 of the substrate 10. A load cell 26is positioned between the base 24 and the cap 22, and one of the base 24and cap 22 is configured to translate the load to the load cell 26. Forexample, the load cell 26 may be secured to the base 24 and the cap 22may translate the load directly or indirectly, through a cell contactsurface 28, to the load cell 26. Alternatively, the load cell 26 may besecured to the cap 22, and the base 24 may directly, or indirectlythrough a different circuit contact surface, transfer the load to theload cell 26. The load cell 26 can also be a strain sensor. A printedcircuit board 30 between the base 24 and the cap 22 processes andoutputs data from the load cell 26 to one or both of the localcontroller 18 and the off-site controller 21. The base 24 providescontainment features to trap the walls of the cap from movinghorizontally while allowing movement of the cap 22 vertically totransfer the load. The containment feature can be a double walledportion 32 on the base 24 in which a corresponding single wall 34 on thecap 22 is received.

The load sensor assemblies 20 can be incorporated into the top, bottomor any portion of the legs 14 of the substrate 10. For aestheticreasons, the cap 22 can have a perimeter 25 sized and shaped to beidentical to a perimeter of a leg 14, with the base 24 fitting withinthe cap 22. Alternatively, the base 24 can have a perimeter sized andshaped to be identical to the perimeter of the leg 14, with the cap 22fitting within the base 24. As illustrated in FIG. 1 , the load sensorassemblies 20 are on the bottom 40 of the leg 14. The load sensorassemblies 20 can be physically attached to the bottom 40 of the leg 14so that they move when the substrate 10 and legs 14 are moved.Alternatively, the load sensor assemblies 20 can be configured with aleg receiver 42, as illustrated in FIGS. 3A and 3B. The leg receivers 42can be shaped to best contain the bottom 40 of the leg 14 whilereceiving the entire load born through the leg 14. The leg receivers 42can be integral with the cap 22 or can be attached to the cap 22. Theload sensor assemblies 20 as shown in FIGS. 3A and 3B with wires 44 thatcan be either power to the load sensor assemblies 20 or can be datatransmitted from the load sensor assemblies 20. The wires 44 can behidden along the leg 14 and frame of the substrate 10 for aesthetics.

FIG. 4 illustrates the load sensor assemblies 20 inline in the middle 46of each leg 14 while FIG. 5 illustrates the load sensor assemblies 20 atthe top 48 of each leg 14. The load sensor assemblies 20 can beincorporated between the substrate frame and the legs 14, for example.The load sensor assemblies 20 can be placed directly on top of the leg14 or can be fitted into a hollow of the leg, so long as the entire loadfrom the substrate 10 to the floor 16 in that location goes through thesensor assembly 20.

The load sensor assemblies 20 can also be incorporated into the castorsof wheels, i.e., between the legs 14 and the castors of substrates thatare on wheels, such as hospital beds.

As illustrated in FIGS. 6A and 6B, the load sensor assemblies 20 can belocated in floor mats 50 that are used to create bays onto which beds onwheels or castors can be rolled and positioned when use of the loadsensor assemblies 20 is desired. The floor mat 50 is sized to have anarea at least as large as an area defined by the legs 14 of thesubstrate 10. The base 24 of the load sensor assemblies 20 can be indirect contact with the floor 16 when incorporated into the mat 50 orcan have some mat 50 intervening between it and the floor 16. The bedcan be rolled onto the mat 50 and positioned such that legs 14 are onthe load sensor assemblies 20. The mats 50 can be positioned on thefloor of a medical facility, for example, to create “bays” in which abed can be rolled into when use of the load sensor assemblies 20 isdesired for a specific patient. Each mat 50 can have a correspondinglocal controller 18 that can communicate with connected devices 19and/or other computers. The load sensor assemblies 20 in the mat 50 canbe wired to the local controller 18 through the matt 50 so the wires arehidden. The local controller 18 can also provide power to the sensorassemblies 20.

The load sensor assemblies can be arranged in the floor 16 on which thesubstrate 10 sits or on which the substrate 10 is positioned, asillustrated in FIG. 7 . For example, the load sensor assemblies 20 canbe placed in an opening in the floor 16 so that the cap 22 is flush withthe floor 16. The substrate 10 may have legs 14 with wheels 52 that canbe rolled over the load sensor assemblies 20 so that the legs 14 aredirectly on the assemblies. The load sensor assemblies 20 can bepermanently positioned in the floor to create “bays” in which a bed canbe rolled into when use of the load sensor assemblies 20 is desired fora specific patient.

To provide for a larger footprint for use with heavy loads, particularlyin hospital and other medical facilities, each load sensor assembly 60can have multiple load cells 26 positioned on the base 24 with the cap22 configured with a cell contact surface 28 configured to translate theload through the respective leg 14 equally to each of the multiple loadcells 26, as illustrated in FIG. 8 . An array of load cells 26 is spacedaround a center of the assembly 60 such that when the leg 14 ispositioned on the assembly 60, the load is spread equally to the loadcells 26. The circuit board 30 is positioned in the base 24. The largefootprint load sensor assemblies 60 can be placed directly on the floor16 and can each further include a ramp 66 to allow for rolling asubstrate 10 such as a hospital bed on wheels up the ramps 66 until thelegs 14 are correctly positioned. The cap 22 can also have anindentation 68 sized to fit a wheel to prevent the wheel from rollingoff of the large footprint load sensor assembly 60 and to help withproper positioning of the respective loads.

In addition, or alternative to the load sensor assemblies described,other types of sensors can be used. Other types of sensors can be usedin a combination with load cells to enhance the accuracy and quality ofdata, in cases where higher resolution is needed, or when theapplication of load cells is not possible or practical based on thecharacteristics of the substrate. For example, when it is not practicalto place more than four legs at the corners of a bed, yet signalacquisition is desired near the middle of the bed. Additional sensorscan also be substituted for load cells in cases where the additionalinformation provided by load cells is not required.

One or more accelerometers 70 can be used with the system 1.Accelerometers measure acceleration forces, which can be static, likethe continuous force of gravity, or may be dynamic, sensing movement orvibrations. This acceleration is caused by tilt with respect to theearth. The substrate “tilts” due to blood flow, physical movement andrespiration of the subject. The output from the accelerometers can beanalyzed in the same way that the output from the load sensor assembliescan be used. The accelerometer(s) can be placed anywhere in or on thelegs as described with respect to the load sensor assemblies 20 or canbe placed anywhere on the substrate 10 itself. However, when theaccelerometer 70 is used in a leg 14 of the substrate 10, flex material72 is positioned under the accelerometer 70 as illustrated in FIG. 9 .The flex material 72 amplifies the signal, allowing for very subtletransfer of motion and providing a higher strength movement signal.

One or more piezoelectric sensors can be used with the system. Thepiezoelectric sensor uses the piezoelectric effect to measure changes inpressure, acceleration, temperature, strain or force by converting themto an electrical charge. Similar algorithms can be applied to the outputfrom the piezoelectric sensors to obtain data pertaining to the subjector subjects on the substrate. Piezoelectric sensors are typicallysheet-like, such that the piezoelectric sensors can be placed directlyunder the substrate or can be placed between the substrate and thesubjects, as examples.

FIGS. 10A and 10B illustrate the use of an optical vibration sensorsystem 80 which uses optical fibers 82. In an optical fiber 82, lighttravels through the core even if the fiber is twisted. Some of the lightsignal degrades within the fiber 82, often due to impurities in theglass but also due to movement of the fiber. The extent that the signaldegrades depends upon the purity of the glass and the wavelength of thetransmitted light. This degradation is used to calculate biometric data.As illustrated, four optical vibration sensor systems 80 are used witheach covering a quarter of the area of the substrate 10. A light source84 provides light to the optical fiber 82 and the signal from eachoptical fiber 82 is transmitted to a respective sensor 86. The length ofthe fiber and the way in which the optical fiber is laid down is known,and the algorithms used to manipulate the sensor data is based in parton these parameters. The way in which the optical fiber is laid down inFIG. 10B is provided as a non-limiting example. FIG. 10A illustrates amattress 90 laid over the optical vibration sensor systems 80, which arepositioned on the substrate 10.

In addition to or alternative to one or more of the load sensorassemblies 20 previously described, a knife edge sensor assembly 100 canbe used, as illustrated in FIGS. 11A and 11B. The knife edge sensorassembly 100 includes a knife edge opening 102 at which light 104 isdirected. For example, the knife edge opening 102 may be formed in theleg 14 of the substrate 10. As another example, the knife edge opening102 may be formed in the body of a sensor that is positioned in the leg14. The sensor, or leg, is positioned on a spring-like device 106, oralternatively, a flexible substrate that is sufficiently flexible toallow for movement of the knife edge opening 102. As pressure is placedon the leg 14, as illustrated in FIG. 11A, the knife edge opening 102moves and some portion of light signal is transmitted through the knifeedge opening 102. The amount of light that is transmitted through theopening 102 equates to a load or motion on the substrate. As illustratedin FIG. 11B, the light signal may be completely interrupted when thereis no load on the substrate. The light 104 is transmitted through theopening 102 to a photodiode 108 that measures the amount of lighttransmitted. From the data from the photodiode 108, presence, movementand weight thresholds can be measured. For example, presence can bedetermined based on a change from no light transmitted to any amount oflight transmitted. Weight thresholds or ranges can be determined from achange from no light being transmitted to a specific amount of lightbeing transmitted, wherein each amount of light corresponds to a weighton the substrate. Movement such as turning over is determined from achange in the amount of light being transmitted. Even movement such asbreathing can be measured based on very small changes in the amount oflight detected and the frequency of those changes.

In addition to or alternative to one or more of the load sensorassemblies previously described, an optical encoder sensor assembly 110can be used, illustrated in FIGS. 12A-12G. The optical encoder sensorassembly 110 includes a template 112 formed in the sensor body, oralternatively, directly formed in the leg 14 of the substrate 10. Thetemplate 112 has multiple openings 114, which can vary in height, orboth height and width, as shown in FIG. 12C. The sensor, or leg 14, ispositioned on a spring-like device 116 or a flexible substrate aspreviously described, that is sufficiently flexible to allow formovement of the template distances approximating the length of thetemplate. A light 118 is positioned to shine though the template 112 andis positioned such that a base line “no presence” on the substrate 10 isknown. The template 112 moves up and down due to forces on the substrate10 such as weight and movement. The progressive variation in templateopening sizes changes the amount of the light that passes through thetemplate 112 and a photodiode 120 on an opposite side of the template112 measures the amount of light. The dividers 122 between openings 114in the template 112 provide reference points. The timing and frequencyof the light passing through can be used to determined weight andmovement of the subject.

The template 112 may be formed of fine, fixed size openings 114. Thefiner slits in the template 112 increases resolution of the lightpassing through, providing for more sensitive measurements. Acombination of templates 112 may be used in the assembly 110 to provideboth large signals and fine signals, illustrated in FIGS. 12E-12G. Thefine-holed template 124 may require less area as the range of movementis much smaller, as shown in FIGS. 12E-12G. The templates 112 can beformed side by side and may only require one light source 118 and onephotodiode 120, as in FIGS. 12E and 12F. The templates 112 can be formedone on top of the other as in FIG. 12G, with two separate light sources118 and photodiodes 120 used. The large signals can provide informationas to presence and weight thresholds or ranges. The large signals canalso provide information as to movements such as turning over on thesubstrate. The fine-holed template 112 can be used to determinebiometrics such as heartbeat and respiration.

In addition to or alternative to one or more of the load sensorassemblies previously described, a polarized sensor assembly 130 can beused. The polarized sensor assembly 130 is illustrated in FIGS. 13A-C.The polarized sensor assembly 130 includes two polarized lenses, onebeing a stationary lens 132 and the other being a movable lens 134. Themovable lens 134 is configured to be moved by a load on the substrate10, the load transferred to the leg 14 and moving the movable lens 134.As a non-limiting example, the movable lens 134 can be a gear with teeth136 along its perimeter. A sensor portion 138 positioned on the leg 14of the substrate 10, or formed in the leg 14 of the substrate 10, alsohas teeth 140, with the teeth 136 of the movable lens 134 and the teeth138 of the sensor portion 138 meshing together. The sensor, or leg, ispositioned on a spring-like device 142 or a flexible substrate aspreviously described, that is sufficiently flexible to allow formovement of the sensor portion 138 to move the movable lens 134 betweenalignment and unalignment with the stationary lens 132. When a load isapplied to the substrate 10, the sensor portion 138 moves, therebymoving the movable lens 134. A light 144 is transmitted to the lenses132, 134, and when the polarized lenses are aligned as in FIG. 13A, thelight is transmitted through the lenses 132, 134. When the polarizedlenses are unaligned to different degrees, the light is filtered todifferent degrees. The light 144 transmitted through the lenses ismeasured with a photodiode 146. The changes in light intensity can beused to measure minute movements that are then ran through thealgorithms to determine data about the subject 12. For example, abase-line of no presence on the substrate may be set to completealignment of the stationary and the movable lenses 132, 134. A weightthreshold or ranges can be determined by an overall large movement ofthe movable lens 134, while minute changes in the light intensity andits frequency can determine respiration and heart rate. Moderate changesin light may indicate movement of the subject 12 on the substrate 10,such as moving a leg or arm.

One or more of any combination of the sensor assemblies described hereincan be used in the systems herein. Each of the sensor assemblies can bepowered with any means known to those skilled in the art. Conventionalelectrical power may be used to power the sensor assemblies, or eachsensor assembly may have a battery. In one example shown in FIG. 14 ,power can be delivered to the sensor assemblies 20 via a fiber opticcable 150. The fiber 150 can be run down the leg 14 to the sensorassembly 20. Light 152 from the fiber 150 is converted to power via asolar cell or photodiode 154 located at the sensor assembly 20 location.Data transmission to the local controller 18 or processor can be wiredor wireless. The same fiber optic cable 150 can be used to transfer datafrom the sensor assemblies 20 to a processor as an alternative to, or inaddition to, BLE or Wifi. One color (wavelength) of light can be usedfor power and a second color (wavelength) can be used for data transfer.

An example of a configuration of the load sensor assemblies 20 for usewith a substrate 10 on which one subject 12 is designed to rest isillustrated in FIG. 15A. Four sensor assemblies 20 are positioned at thelegs 14 in the four corners of the substrate 10. Although four sensorassemblies 20 are illustrated, the system would automaticallyreconfigure for more or less sensor assemblies 20. However, a loadsensor assembly 20 is required at each location in which a load istransferred from the substrate 10 to the floor 16. For a substrate 10′on which two people are designed to rest, nine sensor assemblies 20 maybe used, as illustrated in FIG. 15B. Although nine sensor assemblies 20are illustrated, the system 1 would automatically reconfigure for moreor less sensor assemblies. For example, for beds in which two twins areplaced together, eight sensor assemblies 20 may be used, one for each ofthe four legs of the two twin beds. Using a system 1 with multiplesensor assemblies 20 provides the ability to remove or cancel out orcombine signals from another subject or the environment. The signalsfrom multiple sensors are combined and/or separated to enhance theamplitude, reduce noise and increase the usefulness of variousbiometrics. The use of multiple sensors in a substrate on which twopeople rest provides the ability to map and correlate each person'sweight, position and bio signals while they are on the subject at thesame time. The system can also distinguish between the people when theyare on the substrate alone.

Examples of data determinations that can be made using the systemsherein are described. The algorithms are dependent on the number ofsensors and each sensor's angle and distance with respect to the othersensors. This information is predetermined. Software algorithms willautomatically and continuously maintain “empty weight” calibration withthe sensors so that any changing in weight due to changes in a mattressor bedding is accounted for.

The load sensor assemblies herein utilize macro signals and microsignals and process those signals to determine a variety of data,described herein. Macro signals are low frequency signals and are usedto determine weight and center of mass, for example. The strength of themacro signal is directly influence by the subject's proximity to eachsensor.

Micro signals are also detected due to the heartbeat, respiration and tomovement of blood throughout the body. Micro signals are higherfrequency and can be more than 1000 times smaller than macro signals.The sensors detect the heart beating and can use this amplitude data todetermine where on the substrate the heart is located, thereby assistingin determining in what direction and position the subject is laying. Inaddition, the heart pumps blood in such a way that it causes top tobottom changes in weight. There is approximately seven pounds of bloodin a human subject, and the movement of the blood causes small changesin weight that can be detected by the sensors. These directional changesare detected by the sensors. The strength of the signal is directlyinfluenced by the subject's proximity to the sensor. Respiration is alsodetected by the sensors. Respiration will be a different frequency thanthe heart beat and has different directional changes than those thatoccur with the flow of blood. Respiration can also be used to assist indetermining the exact position and location of a subject on thesubstrate. These bio-signals of heart beat, respiration and directionalmovement of blood are used in combination with the macro signals tocalculate a large amount of data about a subject, including the relativestrength of the signal components from each of the sensors, enablingbetter isolation of a subject's bio-signal from noise and othersubjects.

As a non-limiting example, the cardiac bio-signals in the torso area areout of phase with the signals in the leg regions. This allows thesignals to be subtracted which almost eliminates common mode noise whileallowing the bio-signals to be combined, increasing the signal to noiseby as much as a factor of 3 db or 2× and lowering the common or externalnoise by a significant amount. By analyzing the phase differences in the1 hz to 10 hz range (typically the heart beat range) the angularposition of a person laying on the bed can be determined. By analyzingthe phase differences in the 0 to 0.5 hz range, it can be determined ifthe person is supine or laying on their side, as non-limiting examples.

Because signal strength is still quite small, the signal strength can beincreased to a level more conducive to analysis by adding or subtractingsignals 200, resulting in larger signals. The signal deltas 202 arecombined in signal 204 to increase the signal strength for higherresolution algorithmic analysis, as illustrated in FIG. 16 .

The systems 1 herein can cancel out external noise that is notassociated with the substrate 10. External noise 210, such as the beatof a bass or the vibrations caused by an air conditioner, register asthe same type of signal on all sensor assemblies 20 and is thereforecanceled out when deltas are combined during processing. This isillustrated in FIGS. 17A and 17B. In FIG. 17B, the external noise 210 isshown on each signal 212, with the external noise removed and then thesignals combined in 214.

Using superposition analysis, two subjects can be distinguished on onesubstrate. Superposition simplifies the analysis of the signal withmultiple inputs. The usable signal equals the algebraic sum of theresponses caused by each independent sensor acting alone. To ascertainthe contribution of each individual source, all of the other sourcesfirst must be turned off, or set to zero. This procedure is followed foreach source in turn, then the resultant responses are added to determinethe true result. The resultant operation is the superposition of thevarious sources. By using signal strength and out-of-phase heart rates,individuals can be distinguished on the same substrate.

The systems 1 and sensor assemblies 20 herein provide the ability toprovide dynamic center of mass location and movement vectors for thesubject, while eliminating those from other subjects and inanimateobjects or animals on the substrate. By leveraging multiple sensorassemblies that detect the z-axis of the force vector of gravity, and bydiscriminating and tracking the center of mass of multiple subjects asthey enter and move on a substrate, not only can presence, motion andcardiac and respiratory signals for the subject be determined, but thesignals of a single or multiple subjects on the substrate can beenhanced by applying the knowledge of location to the signal received.By analyzing the bio-signal's amplitude and phase in different frequencybands, the center of mass for a subject can be obtained using multiplemethods, examples of which include:

DC weight;

AC low band analysis of signal, center of mass and back supinerespiratory identification of subject;

AC mid band analysis of signal center of mass and cardiac identificationof subject; and

AC upper mid band identification of snorer or apnea events.

The systems 1 and sensor assemblies 20 can be used to detect presenceand location X, Y, theta, back and supine positions of a subject on asubstrate. Such information is useful for calculating in/out statisticsfor a subject such as: period of time spent in bed, time when subjectfell asleep, time when subject woke up, time spent on back, time spenton side, period of time spent out of bed. The sensor assemblies can bein sleep mode until the presence of a subject is detected on thesubstrate, waking up the system.

Macro weight measurements can be used to measure the actual staticweight of the subject as well as determine changes in weight over time.Weight loss or weight gain can be closely tracked as weight and changesin weight can be measured the entire time a subject is in bed everynight. This information may be used to track how different activities orfoods affect a person's weight. For example, excessive water retentioncould be tied to a particular food. In a medical setting, for example, atwo-pound weight gain in one night or a five-pound weight gain in oneweek could raise an alarm that the patient is experiencing congestiveheart failure. Unexplained weight loss or weight gain can indicate manymedical conditions. The tracking of such unexplained change in weightcan alert professionals that something is wrong.

FIGS. 18A and 18B illustrate an example analysis of center of mass orposition using macro signals. The load sensor assemblies 20 detectingthe entire load on the substrate 10 triangulate a location of the centerof mass by detecting weight measured by each load sensor assembly 20. InFIG. 18A, both load sensor assemblies 20 on the left side of thesubstrate 10 measure a similar weight that is greater than the weightmeasured by the load sensor assemblies 20′ on the right side of thesubstrate 10. The subject 12 is determined to be on the left side of thesubstrate 10. FIG. 18B illustrates the straight forward embodiment wherethe subject 12 is directly in the center of the substrate 10, based oneach load sensor assembly 20 measuring the same weight.

Center of mass can be used to accurately heat and cool particular andlimited space in a substrate 10, with the desired temperature tuned tothe specific subject 12 associated with the center of mass, withoutaffecting other subjects on the substrate 10. Certain mattresses areknown to provide heating and/or cooling. As non-limiting examples, asubject can set the controller 18 to actuate the substrate to heat theportion of the substrate under the center of mass when the temperatureof the room is below a certain temperature. The subject can set thecontroller 18 to instruct the substrate to cool the portion of thesubstrate under the center of mass when the temperature of the room isabove a certain temperature.

These macro weight measurements can also be used to determine a movementvector of the subject. Subject motion can be determined and recorded asa trend to determine amount and type of motion during a sleep session.This can determine a general restlessness level as well as other medicalconditions such as “restless leg syndrome” or seizures.

Motion detection can also be used to report in real time a subjectexiting from the substrate. Predictive bed exit is also possible as theposition on the substrate as the subject moves is accurately detected,so movement toward the edge of a substrate is detected in real time. Ina hospital or elder care setting, predictive bed exit can be used toprevent falls during bed exit, for example. An alarm might sound so thata staff member can assist the subject exit the substrate safely.Alternatively, the legs 14 of the substrate 10 can be configured tolower on the side of the substrate 10 in which the subject 12 isexiting, so that the subject 12 can exit more easily. The legs 14 may betelescoping, for example, so that they increase and decrease in length.The legs 14 may be controlled by the controller 18 that receives thesignals from the sensor assemblies 20 and processes the signals, sendingprogrammed instructions to an actuator that lowers the legs 14 on theappropriate side, as illustrated in FIG. 19 .

The systems 1 and sensor assemblies 20 can be used to determine actualpositions of the subject on the substrate, such as whether the subjectis on its back, side, or stomach, and whether the subject is aligned onthe substrate vertically, horizontally, with his or her head at the footof the substrate or head of the substrate, or at an angle across thesubstrate. The sensors can also detect changes in the positions, or lackthereof. In a medical setting, this can be useful to determine if asubject should be turned to avoid bed sores. In a home or medicalsetting, firmness of the substrate can be adjusted based on the positionof the subject. For example, in FIG. 20 , sleeping angle can bedetermined from center of mass, position of heart beat and/orrespiration, and directional changes due to blood flow.

Controlling external devices such as lights, ambient temperature, musicplayers, televisions, alarms, coffee makers, door locks and shades canbe tied to presence, motion and time, for example. As one example, thecontroller 18 can collect signals from each load sensor assembly 20,determine if the subject is asleep or awake and control at least oneexternal device based on whether the subject is asleep or awake. Thedetermination of whether a subject is asleep or awake is made based onchanges in respiration, heart rate and frequency and/or force ofmovement. As another example, the controller 18 can collect signals fromeach load sensor assembly 20, determine that the subject previously onthe substrate has exited the substrate and change a status of the atleast one external device in response to the determination. As anotherexample, the controller 18 can collect signals from each load sensorassembly 20, determine that the subject has laid down on the substrateand change a status of the at least one external device in response tothe determination.

A light can be automatically dimmed or turned off by instructions fromthe controller 18 to a controlled device when presence on the substrateis detected. Electronic shades can be automatically closed when presenceon the substrate is detected. The light can automatically be turned onwhen bed exit motion is detected or no presence is detected. Electronicshades can be opened when motion indicating bed exit or no presence isdetected. If a subject wants to wake up to natural light, shades can beprogrammed to open when movement is sensed indicating the subject haswoken up. Waking up can be detected by increased movement, more rapidheartbeat, etc. Sleep music can automatically be turned on when presenceis detected on the substrate. Predetermined wait times can be programmedinto the controller 18, such that the lights are not turned off or thesleep music is not started for ten minutes after presence is detected,as non-limiting examples.

The controller 18 can be programmed to recognize patterns detected bythe load sensor assemblies 20. The patterned signals may be in a certainfrequency range that falls between the macro and the micro signals. Forexample, a subject may tap the substrate three times with his or herhand, creating a pattern. This pattern may indicate that the substratewould like the lights turned out. A pattern of four taps may indicatethat the subject would like the shades closed, as non-limiting examples.Different patterns may result in different actions. The patterns may beassociated with a location on the substrate. For example, three tapsnear the top right corner of the substrate can turn off lights whilethree taps near the base of the substrate may result in a portion of thesubstrate near the feet to be cooled. Patterns can be developed formedical facilities, in which a detected pattern may call a nurse.

While the figures all illustrate the use of the sensor assemblies with abed as a substrate, it is contemplated that the sensor assemblies can beused with chairs such as desks, where a subject spends extended periodsof time. A wheel chair can be equipped with the sensors to collectsignals and provide valuable information about a patient. The sensorsmay be used in an automobile seat and may help to detect when a driveris falling asleep or his or her leg might go numb. Furthermore, the bedcan be a baby's crib, a hospital bed, or any other kind of bed.

Implementations of controller 18 and/or controller 21 (and thealgorithms, methods, instructions, etc., stored thereon and/or executedthereby) can be realized in hardware, software, or any combinationthereof. The hardware can include, for example, computers, intellectualproperty (IP) cores, application-specific integrated circuits (ASICs),programmable logic arrays, optical processors, programmable logiccontrollers, microcode, microcontrollers, servers, microprocessors,digital signal processors or any other suitable circuit. In the claims,the term “controller” should be understood as encompassing any of theforegoing hardware, either singly or in combination.

Further, in one aspect, for example, controller 18 and/or controller 21can be implemented using a general purpose computer or general purposeprocessor with a computer program that, when executed, carries out anyof the respective methods, algorithms and/or instructions describedherein. In addition or alternatively, for example, a special purposecomputer/processor can be utilized which can contain other hardware forcarrying out any of the methods, algorithms, or instructions describedherein.

The word “example,” “aspect,” or “embodiment” is used herein to meanserving as an example, instance, or illustration. Any aspect or designdescribed herein as using one or more of these words is not necessarilyto be construed as preferred or advantageous over other aspects ordesigns. Rather, use of the word “example,” “aspect,” or “embodiment” isintended to present concepts in a concrete fashion. As used in thisapplication, the term “or” is intended to mean an inclusive “or” ratherthan an exclusive “or”. That is, unless specified otherwise, or clearfrom context, “X includes A or B” is intended to mean any of the naturalinclusive permutations. That is, if X includes A; X includes B; or Xincludes both A and B, then “X includes A or B” is satisfied under anyof the foregoing instances. In addition, the articles “a” and “an” asused in this application and the appended claims should generally beconstrued to mean “one or more” unless specified otherwise or clear fromcontext to be directed to a singular form.

While the disclosure has been described in connection with certainembodiments, it is to be understood that the disclosure is not to belimited to the disclosed embodiments but, on the contrary, is intendedto cover various modifications and equivalent arrangements includedwithin the scope of the appended claims, which scope is to be accordedthe broadest interpretation so as to encompass all such modificationsand equivalent structures as is permitted under the law.

What is claimed is:
 1. A system for measuring data specific to a subjectusing gravity, the system comprising: a substrate on which a subjectlies, the substrate having multiple legs extending from the substrate toa floor to support the substrate; load sensor assemblies, each loadsensor assembly associated with a respective leg and comprising: a capconfigured to receive a load from the substrate; a base configured toprovide contact with the floor, the base and cap configured to fittogether to maintain alignment of the cap to the base while allowingvertical movement of the cap; a load cell between the base and the cap,one of the base and cap configured to translate the load to the loadcell; and a printed circuit board that processes and outputs data fromthe load cell, wherein a combination of all load sensor assembliesreceive an entire load to which the substrate is subjected.
 2. Thesystem of claim 1, wherein each load sensor assembly is built into therespective leg.
 3. The system of claim 2, wherein the cap has aperimeter sized and shaped to be identical to a perimeter of therespective leg, with the base fitting within the cap.
 4. The system ofclaim 2, wherein each load sensor assembly is built into a top of therespective leg, the base formed by the top of the respective leg and thecap in contact with the substrate, each load sensor assembly configuredto receive all load translated through the respective leg.
 5. The systemof claim 2, wherein each load sensor assembly is located in-line with anupper portion and a lower portion of the respective leg and configuredto receive all load translated through the respective leg.
 6. The systemof claim 2, wherein each load sensor assembly is located at a bottom ofthe respective leg, the cap formed by the bottom of the leg and the basein contact with the floor, each load sensor assembly configured toreceive all load translated through the respective leg.
 7. The system ofclaim 1, wherein the cap has a single sidewall and the base has a doublesidewall configured to receive the single sidewall of the cap, thedouble sidewall configured to restrain the cap from lateral movementwhile allowing movement in a vertical direction.
 8. The system of claim1, wherein each leg has a wheel and each load sensor assembly is locatedin the floor such that the cap is flush with the floor, each load sensorassembly spaced such that a load sensor assembly is under the respectiveleg of the substrate when the substrate is rolled into a use position.9. The system of claim 1, further comprising a floor mat, wherein eachload sensor assembly is located in the floor mat, the floor mat sized tohave an area at least as large as an area of the substrate, each loadsensor assembly positioned within the mat such that each load sensorassembly is under the respective leg of the substrate when the substrateis positioned on the mat.
 10. The system of claim 1, wherein each loadsensor assembly comprises multiple load cells positioned in the base,the cap configured with a circuit contact surface configured totranslate the load equally to each of the multiple load cells.
 11. Thesystem of claim 1, further comprising a controller in communication witheach load sensor assembly, the controller configured to collect signalsfrom each load sensor assembly and determine a center of mass of thesubject on the substrate.
 12. The system of claim 1, further comprisinga controller in communication with each load sensor assembly and atleast one external device in communication with the controller, thecontroller configured to: collect signals from each load sensorassembly; determine if the subject is asleep or awake; and control theat least one external device based on whether the subject is asleep orawake.
 13. The system of claim 1, further comprising a controller incommunication with each load sensor assembly and at least one externaldevice in communication with the controller, the controller configuredto: collect signals from each load sensor assembly; determine that thesubject previously on the substrate has exited the substrate; and changea status of the at least one external device in response to thedetermination.
 14. The system of claim 1, further comprising acontroller in communication with each load sensor assembly and at leastone external device in communication with the controller, the controllerconfigured to: collect signals from each load sensor assembly; determinethat the subject has laid down on the substrate; and change a status ofthe at least one external device in response to the determination.
 15. Asystem for measuring data specific to a subject using gravity, thesystem comprising: a substrate on which a subject rests, the substratehaving multiple legs extending from the substrate to a floor to supportthe substrate; at least two load sensor assemblies, each load sensorassembly associated with a respective leg configured to measure a staticload and changes in load on the substrate through the leg; a controller;and communication means from each of the at least two load sensorassemblies to the controller, wherein the controller processes outputfrom each of the at least two load sensor assemblies.
 16. The system ofclaim 15, wherein each load sensor assembly comprises: a cap configuredto receive a load from the substrate; a base configured to providecontact with the floor, the base and cap configured to fit together tomaintain alignment of the cap to the base while allowing verticalmovement of the cap; a load cell between the base and the cap, one ofthe base and cap configured to translate the load to the load cell; anda printed circuit board that processes and outputs data from the loadcell to the processor.
 17. The system of claim 16, wherein each loadsensor assembly is built into the respective leg and the cap has aperimeter sized and shaped to be identical to a perimeter of therespective leg.
 18. The system of claim 15, further comprising at leastone external device in communication with the controller, the controllerconfigured to: collect signals from each load sensor assembly; determineif the subject is asleep or awake; and control the at least one externaldevice based on whether the subject is asleep or awake.
 19. The systemof claim 1, further comprising at least one external device incommunication with the controller, the controller configured to: collectsignals from each load sensor assembly; determine that the subjectpreviously on the substrate has exited the substrate; and change astatus of the at least one external device in response to thedetermination.
 20. The system of claim 1, further comprising at leastone external device in communication with the controller, the controllerconfigured to: collect signals from each load sensor assembly; determinethat the subject has laid down on the substrate; and change a status ofthe at least one external device in response to the determination.